The present invention relates to a method for fixing a bearing member for a cylindrical substrate, a structure for fixing a bearing member for a cylindrical substrate, an electrophotographic photoreceptor having a bearing member, a print cartridge, and an apparatus for forming an image.
In general, a cylindrical electrophotographic photoreceptor has been produced forming a photosensitive layer on an outer periphery of a cylindrical substrate formed of aluminum or an aluminum alloy, and interdigitating a fitting called a flange formed of a resin and an aluminum alloy on one end or both ends thereof by adhesion or other measures, and has been used while the flange is a rotation center.
In recent years, duplicators and printers are generally demanded to print a color image and a high quality image, and commercially available products are having such capabilities of a color image and a high quality image. According to the trend, in an apparatus for forming an image employing an electrophotographic photoreceptor, the electrophotographic photoreceptor constituting a core component thereof is demanded to have higher deflection precision on rotation.
In a conventional electrophotographic photoreceptor having a flange, as shown in FIGS. 6A and 6B, a flange 62 is interdigitated on an end of an electrophotographic photoreceptor 60, a hole is formed at the central part of the flange 62, and an axis member 66 fixed on a supporting member 64 is inserted into the hole to support the electrophotographic photoreceptor 60 freely rotatable. Alternatively, while not shown in the figures, an axis member 66 is fixed at the central part of the flange 62, and the axis member 66 is supported by a hole provided in a support member 64 freely rotatable.
The electrophotographic photoreceptor having a flange has the following problems.
(1) Because the photosensitive layer is formed on the outer periphery of the electrophotographic photoreceptor, and the flange is interdigitated into the inner surface thereof, it has a coaxiality error caused by the difference between the outer periphery and the inner surface of the substrate.
(2) The flange has the hole or the axis united with the flange, which becomes the rotation center of the electrophotographic photoreceptor having the flange. Therefore, in the case where the hole is formed, it has a coaxiality error caused by the difference between the outer periphery and the inner surface of the flange, and in the case where the axis is united with the flange, it has a coaxiality error caused by the difference between the outer diameter of the axis and the outer diameter of the interdigitating part of the flange.
(3) It has an error caused by the difference between the inner diameter of the electrophotographic photoreceptor and the outer diameter of the interdigitating part of the flange, and thus the interdigitation is imperfect.
(4) The electrophotographic photoreceptor having a flange formed by interdigitating the flange and the electrophotographic photoreceptor united with each other is installed in a print cartridge while the hole or the axis of the flange is the rotation center, so as to constitute an apparatus for forming an image by an electrophotographic imaging process. Therefore, in the case where the electrophotographic photoreceptor having the flange slides by rotation, it causes a coaxiality error caused by the difference between the inner diameter and the outer diameter thereof.
(5) The conventional technique involves a number of factors causing a rotation error although it is constituted with a small number of components, and there is a limitation in improving the precision in rotation deflection by a method of low cost.
(6) Because the flange is fixed to the electrophotographic photoreceptor by a measure, such as adhesion or crimping, it is extremely difficult to reuse the electrophotographic photoreceptor and the flange by detaching. Furthermore, it is difficult to shorten the time required for the operation of interdigitating and fixing the flange to the electrophotographic photoreceptor, and an apparatus for interdigitating and fixing the flange to the electrophotographic photoreceptor is complex and expensive.
The invention has been made to solve the problems associated with the conventional techniques and provides the following.
(1) The invention relates to, as an aspect, a method for fixing a bearing member for a cylindrical substrate containing a step of inserting an inserting member into a cylindrical substrate from an end of the cylindrical substrate to expand the cylindrical substrate in a direction toward an outer periphery thereof by an expanding function in a diameter direction caused by elasticity of the inserting member, whereby the cylindrical substrate and a bearing member interdigitated on an outer periphery of the cylindrical substrate are clamped on each other.
(2) The invention also relates to, as another aspect, a structure for fixing a bearing member for a cylindrical substrate containing a cylindrical substrate, an inserting member having an expanding function in a diameter direction caused by elasticity thereof upon inserting in the cylindrical substrate from an end of the cylindrical substrate, and a bearing member interdigitated on an outer periphery of the cylindrical substrate.
(3) The invention relates to, as still another aspect, an electrophotographic photoreceptor having a bearing member containing an electrophotographic photoreceptor, an inserting member having an expanding function in a diameter direction caused by elasticity thereof upon inserting in the electrophotographic photoreceptor from an end of the electrophotographic photoreceptor, and a bearing member interdigitated on an outer periphery of the electrophotographic photoreceptor.
(4) The invention also relates to, as a further aspect, a print cartridge having the electrophotographic photoreceptor having a bearing member according to the invention installed therein.
(5) The invention also relates to, as a still further aspect, an apparatus for forming an image having the electrophotographic photoreceptor according to the invention.
In the invention, clamping of the cylindrical substrate and the bearing member interdigitated on an outer periphery of the cylindrical substrate is attained by expanding the cylindrical substrate in the direction toward the outer periphery thereof based on the expanding function in the diameter direction caused by elasticity of the inserting member upon inserting in the cylindrical substrate form an end of the cylindrical substrate.